Wind slabs will be likely on NW-N-NE-E-SE aspects near and above treeline as new snow and gale force SW winds impact our area today. These wind slabs will continue to grow throughout the day and will be large enough in size to injure or bury a backcountry user.

Look for clues to where wind slabs are forming such as blowing snow, cornice formation, and wind pillows. Avoid terrain with new wind slab development.

Avalanche Problem 2: Storm Slab

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As snowfall intensity increases this morning, storm slabs will become likely on all aspects in below treeline and near treeline terrain. Snow levels are generally forecasted to drop throughout the day but an upside down storm snow structure could exist in many areas. In isolated open below treeline terrain, there remains the possibility that surface hoar has been buried under the recent storm snow. If this occurs, easily triggeredavalanches would be likely on lower angle slopes.

Look for clues such as snow surface cracking and avoid areas where unstable snow exists.

Avalanche Problem 3: Loose Wet

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Areas of rain on snow today will be prone to loose wet avalanche activity. This is most likely to occur below 8000' on slopes steeper than 35 degrees and should diminish as snow levels are forecasted to drop to near 6000' later this morning. Loose wet avalanche activity today could be either natural or human triggered. Terrain traps such as creek beds and road cuts could increase the depth of avalanche debris associated with otherwise small loose wet avalanches.

Observations were made yesterday on Andesite Peak (Donner Summit area). Small storm slabs and winds slabs were forming throughout the morning hours in this area and were able to be intentionally triggered. 3 to 5'' of new storm snow existed in this area. Temperatures and snow levels were rising throughout the morning creating an upside down storm snow structure with heavier storm snow on top of lighter snow. Loose wet avalanches were observed on the drive to the trailhead at elevations below 7200'. Buried surface hoar was not found in many open below treeline locations in this area.

Weather and CURRENT CONDITIONS

weather summary

A winter storm warning is in effect until 4am Saturday. Overnight and into the morning hours, snow levels were in the 7500-8500' range. They should drop this morning with the next band of moisture coming down to around 6000'. The higher elevation Sierra could pick up 1 to 2 feet of snow by early Saturday morning. On Saturday, most moisture will stay along the Sierra crest north of Hwy. 50 with on and off showers. After a break on Sunday, another series of storms will move into the area late Sunday night through at least Wednesday.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS

For 7000 ft. to 8000 ft.

Friday

Friday Night

Saturday

Weather:

Cloudy. Rain in the morning, snow through the day.

Cloudy. Snow.

Mostly cloudy. Chance of snow.

Temperatures:

31 to 36 deg. F.

23 to 28 deg. F.

34 to 39 deg. F.

Mid Slope Winds:

SW

SW

SW

Wind Speed:

20 to 30mph. Gust to 75mph.

20 to 30mph. Gusts to 75mph decreasing to 65mph after midnight.

20 to 30mph with gusts to 55mph.

Expected snowfall:

4 to 10

4 to 8

Up to 1

For 8000 ft. to 9000 ft.

Friday

Friday Night

Saturday

Weather:

Cloudy. Snow.

Cloudy. Snow in the evening then snow likely after midnight.

Mostly cloudy. Chance of snow showers.

Temperatures:

28 to 33 deg. F.

22 to 27 deg. F.

29 to 35 deg. F.

Ridge Top Winds:

SW

SW

SW

Wind Speed:

35 to 45mph with gusts to 100mph.

30 to 50mph with gusts to 100mph.

25 to 40mph with gusts to 80mph.

Expected snowfall:

4 to 10

6 to 8

Up to 1

Disclaimer

This avalanche advisory is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This advisory covers the Central Sierra Nevada Mountains between Yuba Pass on the north and Ebbetts Pass on the south. Click here for a map of the forecast area. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258

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This website is owned and maintained by the non-profit arm of the Sierra Avalanche Center. Some of the content is updated by the USDA avalanche forecasters including the forecasts and some observational data. The USDA is not responsible for any advertising, fund-raising events/information, or sponsorship information, or other content not related to the forecasts and the data pertaining to the forecasts.